When the project of the same name was created immediately
after closing the project
and deleting the folder of the project outside IDE,
the error had occurred inside. messages.log is attached.
[ step ]
1. File > New Project >
Categories:NetBeans Plug-in Modules, Projects:Module Project
2. Next >
Project Name:MyFirstModule
3. Next >
Code Name Base: org.myorg.myfirstmodule
4. Finish >
5. File > Close "MyFirstModule"
* The project folder "MyFirstModule" is deleted outside IDE.
* 1 to 4 is repeated.
* Here, the error was outputted to messages.log.
6. File > New File
Categories: NetBeans Module Development, File Types: Action
* Here, the Null Pointer exception has happened.
7. Next > Next > Next >
8. Class Name: MyFirstAction, Display Name: My First Action
* Even if it can do well, the error may be outputted.

I would like to integrate for 5.1 M1. Presuambly also other similar tasks
(move/rename/copy). But could be worked on separately, I believe from the first
look at the Project API. Do not know that too much yet :)

Continuing....
1. do the clean to allow a clean deletion
2. do not hardcode build.xml
3. deleting also .cvsignore which is generated under certain conditions
(question? - is this a good idea?)
test/unit/ui/ModuleOperationsTest.java; 1.2 -> 1.3;
ui/ModuleOperations.java; 1.1 -> 1.2;